Rubio rejected Obama’s decision to re-engage diplomatic relations with Cuba and said that re-engagement has only boosted Cuba’s communist regime.

"The fact of the matter is that after these changes were made, there are now millions and hundreds of millions of dollars that will flow to the Castro regime," Rubio said and pointed out that Cuba has not witnessed any democratic reforms since the Obama-led diplomatic opening.

"The only thing that has changed as a result of this opening is that now, the Cuban government has more sources of money from which to build out their oppressive apparatus and maintain themselves there permanently," Rubio said. "And we asked nothing in return."

When CNN anchor Dana Bash asked Trump whether he would continue diplomatic relations with Cuba as president, he said he wanted to "make a good deal."

"I would want to make a strong, solid, good deal, because right now everything is in Cuba's favor. Right now everything, every single aspect of this deal is in Cuba's favor," Trump said and was met with laughter from the audience.

Then, when asked whether he would close the U.S. embassy in Havana, Trump again staked his answer in making a good deal.

"I would probably have the embassy closed until such time as a really good deal was made and struck by the United States," Trump said and the audience laughed.

Rubio rejected Trump’s answer and said that the question of closing the embassy is irrelevant, since it is in the same building as the former consulate, so it "can just go back to being called a consulate."

He mocked Trump’s claim that Cuba would sue America and said that he "didn’t know where Cuba is going to sue [the U.S.]," but "if they sue us in a court in Miami, they’re going to lose."

Finally, he re-defined Trump’s claim that a good deal is necessary and said that a good deal already existed: Cuba, he said, must give in to U.S. demands and show signs of democratic opening in order to have diplomatic relations with America.

"Here’s a good deal: Cuba has free elections, Cuba stops putting people in jail for speaking out, Cuba has freedom of the press, Cuba kicks out the Russians from Lourdes and kicks out the Chinese listening station … Cuba stops helping North Korea evade U.N. sanctions, Cuba takes all of those fugitives of American justice, including that cop killer from New Jersey, and send her back to the United States into jail where she belongs."

"Then we can have a relationship with Cuba," Rubio said. "That's a good deal."